It is common for a flat roof, that is a roof having a surface that is substantially horizontal, to support various other structures such as air conditioners, heaters, signage, vents, stacks, and so forth. Such structures include support elements that extend through the surface of a generally horizontal roof and require a seal around the base of the projecting support element where it penetrates the roof with the seal binding to a portion of the element that extends vertically from the surface of the roof and binding to the water resistant roofing material. The seal prevents water and the like from the environment from penetrating the roofing material at the base of the projecting element.
To seal the base of a projecting element against the roof, it is common to provide a “pitch pan” or a “pitch pocket”. The pitch pocket consists of a frame around the base of the projecting element and above the waterproofing material that protects the roof against rainwater and the like. The frame is then filled with an appropriate sealing material such as a tar and forms an insulating mass around the base of the projecting element thereby preventing water from the elements from working its way below the layer of roofing material.
Originally, pitch pockets and the like were formed by cutting metal cans of the type used to retain coffee and the like or of sheet metal. The pitch pockets were configured with an upstanding wall that surrounds the perimeter of a projecting element extending through a roof and a flange extending radially outwardly of the wall. The enclosure formed by the wall would then be filled with the sealing material a portion of which would be applied over the radial flange to assist in retaining the metal enclosure to the roof of the building. The formation of an enclosure suitable for a pitch pocket has been time consuming and in many cases the end product has been unsatisfactory. There has therefore been a demand for a commercially available pitch pocket.
Several forms of commercial pitch pockets are available. For example, Goodman, U.S. Pat. No. 4,928,443 discloses a pocket formed by a elongate strip with a male connector at one end and a female connector at the other end such that the strip can be wrapped around a projecting element and the ends connected to form a circular enclosure. Orth, U.S. Pat. No. 4,937,991 discloses the use of two identical upwardly projecting half-cylinders that can be assembled around a projecting element to form a pitch pocket. Barksdale, U.S. Pat. No. 4,934,117 also discloses the use of a ring to form a pitch pocket. One drawback regarding all the forgoing prior art devices is that the pitch pocket formed is of a predetermined size that can neither can be constricted to seal around a small projecting element nor expanded to seal around a larger projecting element.
Georgeau, U.S. Pat. Nos. 5,493,827 and 5,768,838 both disclose the use of blocks of various sizes including longitudinal blocks and corner blocks that can be glued end to end to form a pitch pocket of any desired size. Georgeau requires that a roofer maintain on hand blocks of many different sizes and shapes. Hindall, U.S. Pat. No. 3,838,544 discloses the use of a plurality of metal parts that can be assembled together to form a pitch pocket of a desired size. Like Georgeau, the Hindall device also requires that a roofer maintain parts of various sizes and shapes in order to assemble a pitch pocket of any desired size.
It would be desirable, therefore, to provide a durable, simple to use part, any two of which could be assembled to each other to form a pitch pocket that would not be limited to a single size, but could be enlarged or reduced in size as needed.